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lIL.s ,TEVB1\Is., Process and .Apparatus for Reducing Ores. No. 229,060. l Patented June 22,1880.

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4L. STEVENS. Y Process and Apparatus zfor Reducing Ores. No1 229,060. Patented .lune 22,1880.

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Us. f3 jf-1 MT1-:D STATES LEVI STEVENS, OF WASHINGTON, DISTRICT OF COLUMBIA.

i* SPECIFICATION forming part of Letters Patent No. 229,060, dated June 22, 1880.

Application filed March G, 1880.

To all whom t may concern Be it known that I, LEVI STEVENS, of Washington, in the District of Columbia, have invented a new and Improved Combined Roasting, Matting, and Smelting Furnace; and I hereby declare the following to be a full. clear, and exact description thereof, reference being had to the accompanying drawings, of w nich- Figure l is a perspective view of my furnace; Fig. 2, a vertical section of the same, taken on the line y y, Fig-4; Fig. 3, a transverse section taken on the line z z, Fig. 4; Fig. 4, a longitudinal section through the center ofthe entire furnace; Fig. 5, a vertical section on the line .fr fr, Fig. 4, showingI a rear view of the furnace proper; and Fig. G, a sectional plan view, the section being taken on the irregular line a, x', Fig. 4.

My invention relates to an improved furnace, triple in its character, whereby it performs the threefold oiiice of smelting, matting, and roasting the ore in one continuous operation; and it consists .in the several and joint construction of the parts whereby, iirst, the requisite degree of combustion is attained, and whereby, secondly, the products of combustion, after performing their function of smelting the ores, operate further successively to mat and roast the same preparatory to smelting.

My invention further consists in an improved process of reducing ores by forcing superheated steam, together with air, through incandescentv coal in the gas-generator, thereby producing rapidly a large quantity of gas of high heating quality, and conveying the gas inamed, in' its highly-heated condition, immediately to or upon the ore.A

My invention further consists in placing a hot-air chamber in the top of the gas-generator,

in connection with an air-jacket, covering or.

partly covering the top of the furnace, through which air-jacket I force atmospheric air, which serves to absorb the heat that would otherwise be radiated from the top of the furnace, and convey it to the hot-air chamber, from which it is discharged in the'form of a hotblast to perfect the combustion of the gases as they pass the bridge-wall.

My invention further consists in having the body of the furnace ofthe form of an inclined (N o model.)

shaft, comprising, in sequence, a smelting, a matting, and a roasting chamber, and in forniing the bed of the last of a series of shelves above the matting furnace with openings, through which air is admitted, and through which, also, the ores can be moved from any shelf to the next below, and so on down, exposing the said ores to the action of the heat from within the furnace, and also to airdrawn iu through the openings as they are moved from the upper to the lower shelves, and keeping each charge of ore separate from the more thoroughly roasted orc below and the less thoroughly roasted ore above until moved into the matting-furnace from the lowest shelf', all as hereinafter more fully set forth.

In the drawings,A represents the smeltingdivision of-my furnace ofthe reverberatory pattern; B, the matting-division, and O the roastiiig-division. These three parts form one continuous chamber or passage, having its bed inclined downward from the feed-hopper a to the point at which it takes the usual upward curve in the smelting portion.

The bed of the roasting portion of the chamber is formed of a series of parallel shelves, D, set into the side walls, E, and only slightly inclining downward from the horizontal from rear to front. The rear edges of these shelves form the only inclosure to the bed at this part, thus allowing unobstructed communication to subsist between the interior of the chamber Aand the external air through the intervening spaces b.

The incline of the bed of the roasting portion O, it will be seen, is steeper than that of theniatting portion B 5 but this is much more than compensated for by the shelf like arrangement of the former, which so obstructs the downward progress of the ore that its descent has to be aided from without.

The bed and sides of the matting and smeltin g portions of the furnace are provided with a water-jacket, o, having an inlet-pipe, d, and a discharge-pipe, d'.

The lire-box F of my furnace, or, asl term it, for reasons-'which will presently appear, the gas-gene1ator,7 is made deep and is provided with curved grate-bars e, dividing it from the ash-pit G below.

H is an internal downward projection of the IOO top of the gas-generator, falling short of the front wall, I, and thus forming the feed-chute f, which opens through the top and is provided with a cover, g. This interior projection extends down below the level of the bridgewall h, thus giving to the passage t', which leads from the gas-generator to the smeltingchamber, the form of a right angle, as shown in Fig. 4. The interior ofthe projection H is hollow, forming the chamber K, which is provided at its base with ports 7s, leading into the passage z in line, or nearly so, with the center of theV horizontal part of said passage. The chamber K opens through its top into the airjacket L, which may cover the entire top M of the furnace, as shown, or may fall short of the Aupper end to such extent as may appear desirable. The air-jacket is provided at its up per end with pipes or openings Z for the admission or injection of air.

The device for producing the combined steam and air blast comprises a pipe, N, leading from a steam-superheater, (not shown,) said pipe lying nearly against the wall of the ash-pit, near its base, and being provided with jet-pipes m, which enter conical ports a, of greater diameter than the said jet-pipes, and extending through to the interior of the ash-pit.

This being the construction of the furnace,

the operation is as follows: The lire having been built in the gasgenerator or fire-box, and the fuel allowed to attain a state of incandescence, the ore is charged through the hopper a, and steam from the superheater, raised to a temperature of from 6000 to 800O Fahrenheit, injected through the pipes N m into the ash-pit, the doors 0 and p being now kept closed. This injection of steam produces, of course, a powerful blast of air through the ports a, and the commingled dry steam and air are thus forced upward through the incandescent fuel. The effect of this is to decompose the steam into its constituent elements, thus greatly accelerating the combustion of the fuel and developing heat of great intensity.

The hot products of combustion assume rst a vertical and then a horizontal course on their way to the smelting-chamber C, owing to the form of the passage t', and at their turn` ing-point they are met by the current of hot air which rushes in through the ports 7c, and which, having been originally admitted or inprogress not only the heat of the top of the furnace, which otherwise would have been lost by radiation, but also the extreme heat of the` chamber K, which serves to raise it to a temperature approximating that of the products of combustion thelnselves, which it encounters in the passage t'. The effect of all this is not only to produce almost absolute combustion of the fuel, but also to multiply the qualitity of inflammable material by reason of the additional hydrogen or carbureted hydrogen wherein they encounter air entering through the openings b, which serves to ignite them afresh, thus aiding the operation of roasting. This accomplished, they nally pass into the chimney O and make their escape.

The ore in the roasting portion of the furnace is distributed down the series of shelves D, each one of which is designed to hold a charge.

ln order to remove a charge from any shelf to the next lower it is pushed over the edge through the proper opening b. This construction serves to keep each charge separate from the more thoroughly roasted ore below, and also from the less thoroughly roasted ore above, as already stated; and whenever a perfectlyroasted charge is removed from the lowest shelf into the matting-chamber all the remaining charges are brought down one shelf lower and a fresh charge introduced upon the uppermost shelf through the hopper a.

The molten metal runs oif into a receptacle, Q, and the slag is removed through a trough, i', all in the usual manner.

Vhat I claim as new, and desire to secure by Letters Patent, is`

l. The process of reducing ores herein described, which consists in forcing superheated steam, together with air, through incandescent coal in the gas-generator, thereby producing rapidly a large quantity of gas of high heating quality and conveying the gas intlamed, in its highly-heated condition, immediately to or upon the ore, substantially as set forth.

2. The top M of the furnace, provided with an air-jacket, L, having openings l for the admission or injection of air, in combination with a hot-air chamber, K, in the top of the gas-generator, said chamber being provided with openings k, substantially as and for the purpose set forth.

3. A furnace for reducing ores in which an inclined shaft connecting the fire-box with the chiinuey comprises, in sequence, a smelting, a matting, and a roasting chamber, and in which the bed of said roasting-chamber consists of a series of shelves with intervening openings, through which air is admitted and the ores moved from shelf to shelf, substantially as described.

LEVI STEVENS.

In presence of B. A. SMITH, N. J. BURNHAM.

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